This invention relates to fluid brake control systems, and while the invention is subject to a wide range of applications, a preferred embodiment of the invention will be particularly described as applied to a fluid brake control system having a brake application and release control device including a plurality of poppet type valves.
The present invention is an improvement over currently used brake application and control devices such as the service slide valve of the well-known ABD control valve generally used for governing service application and release of brakes of freight cars. This service slide valve is operated by a differential abutment comparing auxiliary reservoir and brake pipe pressures in respective chambers on opposite sides of the abutment which actuates the slide valve selectively to different control positions for respectively charging reservoirs, applying pressure to a brake cylinder, and releasing pressure from the brake cylinder. These valves are costly to manufacture, and are somewhat slow to respond because of sliding friction.
Smooth and efficient application and release of brakes of a train is dependent upon the speed at which a change in control is passed along from car to car, beginning at the front end of a train. It is therefore very important that there be as little delay as possible in the successive operation of the service valves for the respective cars of a train. It is therefore highly desirable to increase the speed of propagation of a braking change through a train over the rate of operation currently possible with ABD service slide valves.
An object of the present invention is to provide a fluid brake control system having an improved brake application and release control device which substantially obviates one or more of the limitations and disadvantages of the described prior systems.
Another object of the present invention is to provide a fast operating brake application and release control device.
Another object of the present invention is to reduce manufacturing and maintenance cost of a brake application and release control device.
Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawing, and in part pointed out as the description of the invention progresses.